This reminds of the infamous GPU issues of the unibody models (the last non-retina ones). I have one such 2012 15" MBP which has a dedicated GPU which, as I understand it, has developed soldering issues.
Non-Mac OSs don't know how to turn this GPU on out of the box, so it just sits there without bothering anybody. But, for some reason, MacOS turns it on and it craps the bed, rendering the machine unusable.